2021 West Nile Virus Activity
This map details mosquitoes, dead birds, chickens, and horses that have tested positive for West Nile virus. You can zoom in and out of the map and click on the placemarkers to get a detailed description of the date the positive activity was confirmed and the approximate location.
For information regarding human cases, please click here.
Mosquito Samples: 8
| n | Date Collected | City | Cross Streets | Species |
|---|---|---|---|---|
| 1 | 6/29/21 | Byron | Western Farms Ranch Rd | Culex tarsalis |
| 2 | 7/13/21 | Brentwood | Orwood Rd x Levee Rd | Culex tarsalis |
| 3 | 8/10/21 | Discovery Bay | Cherry Hills Dr | Culex tarsalis |
| 4 | 8/10/21 | Brentwood | Fletcher Ln | Culex tarsalis |
| 5 | 8/30/21 | Discovery Bay | Cherry Hills Dr | Culex pipiens |
| 6 | 9/8/21 | Brentwood | Holland Tract | Culex tarsalis |
| 7 | 9/8/21 | Brentwood | Orwood Rd x Levee Rd | Culex tarsalis |
| 8 | 9/20/21 | Oakley | Main St x Oakley Rd | Culex tarsalis |
Dead Birds: 3
| n | Date Reported | City | Cross Streets | Species |
|---|---|---|---|---|
| 1 | 8/21/21 | Brentwood | Sand Creek Rd x Minnesota Ave | CA Scrub Jay |
| 2 | 9/20/21 | San Pablo | Birmingham Dr x Groom Dr | American Crow |
| 3 | 9/25/21 | Martinez | Morello Ave x Midhill Rd | American Crow |
Sentinel Chicken Flocks: 0
Note: Chickens do not die from West Nile virus. They develop antibodies to the virus which is detected in their blood.
Horses: 0
| n | Date Reported | City | Dead/Euthanized |
|---|---|---|---|